Ultra-short, single-walled carbon nanotube capsules
(US-tubes) internalized with aqueous gadolinium-ion clusters (Gadonanotubes)
are a dual modal MRI contrast agent capable of decreasing both T1 and T2*. The
magnetic properties of both the empty, US-tube nanocapsules and the
Gadonanotubes were measured via SQUID magnetometry. The results suggest the
empty US-tube nanocapsules have a superparamagnetic domain, while the
internalized aqueous Gd3+-ion clusters of the Gadonanotubes posses a separate
paramagnetic domain. These two domains together allow for significant
shortening of both T1 and T2*.